American Spider Beetles

( Mezium americanum )


SIZE: Adult spider beetles are between one-sixteenth and three-sixteenths of an inch in length, depending on species.

COLOR: Most species of spider beetles are golden or reddish-brown.

BEHAVIOR: Spider beetles are not frequent home invaders. However, when they do enter homes they can become a major pest concern due to their habit of feeding on stored food products. Many of these beetles are attracted to flour, wheat and corn. They may also feed on bones, leather, seeds and dried fruit. Different species include hairy, whitemarked, brown, Australian, golden and the American spider beetle. These beetles mostly scavenge for food at night and can be difficult to detect because they often hide in cracks or crevices and avoid the light. These beetles produce larvae that spin webbing as they feed.


Spider beetles are found across the globe and are a particular problem in the Northern region of the United States. They commonly infest packaged or stored food in homes and are also found in food stored within animal nests. They are also frequently spotted in large buildings such as warehouses, museums and libraries. They are attracted to moisture and excrement and are capable of surviving in freezing temperatures.

Tips for Control

Spider beetles can be hard to control because they are difficult to find. Management of these pests requires a thorough home cleaning. This should include:

  • Identifying infestations by searching for webbing left behind by larvae in sources of food.

  • Discarding any products that have been stored for long periods of time without proper containment (this includes pet foods and rodent bait).

  • Cleaning cabinets and shelves where food has been stored.

  • Contacting a pest management professional if a serious infestation has occurred.